1. Field of the Invention
The present invention relates to a technology to configure in an access point and terminal an encryption key used to encode data transmitted wirelessly between the access point comprising a wireless LAN transponder and the terminal that includes a LAN connection device.
2. Description of the Related Art
Various wireless LAN security technologies that prevent unauthorized network access or leakage to third parties of the contents of communications have been proposed in the conventional art. For example, a technology (hereinafter referred to as ‘MAC address restriction’ technology) has been proposed whereby a MAC (Media Access Control) address that constitutes a unique ID signal pre-assigned to a wireless LAN connection device (such as a wireless LAN adapter) installed in a terminal is registered with an access point, the access point authenticates the MAC address at the time of terminal access, and a request for network access from a terminal having a MAC address different from the registered MAC address is denied (see, for example, Japanese Patent Laid-Open No. 2001-320373). A technology (hereinafter referred to as ‘WEP encoding’) has also been proposed whereby a WEP (Wired Equivalent Privacy) key using a desired text string is registered as a common encryption key for both the terminal and the access point and the contents of data exchanged between the terminal and the access point are encrypted using this WEP key, such that even if the data leaks, the contents of the data are difficult to interpret and the data cannot be understood (see, for example, Japanese Patent Laid-Open No. 2001-345819).
However, in the conventional technologies described above, when the terminal seeks to connect to the wireless LAN, the registration of the MAC address with the access point or the setting of the WEP key in the access point and the terminal must be performed manually, making the wireless LAN configuration operations cumbersome and inconvenient. Particularly in the case of a so-called ‘free spot’ that provides an Internet connection by making an access point available in a public space, large numbers of persons want to use the free spot, and their numbers are increasing steadily. Requiring all of these persons who bring their own terminals to perform complex terminal operations such as MAC address registration and WEP key setting as a condition of using the free spot would be extremely inconvenient and impractical.
Furthermore, because the WEP key can serve as a clue to assist in the interpretation of the data exchanged between the terminal and the access point, the newly proposed wireless LAN configuration method must incorporate sufficient measures to prevent the WEP key from leaking during the configuration process and to preserve the confidentiality of the terminal user's communications.